In Preferences/Editor/Features, the line wrapping checkbox is checked, but when opening a file or creating a new one, it is disabled and needs to be manually enabled in the top menu of the document.
I installed Geany 2.0 using the official DMG on a Macbook Pro 13" M1 2020 running MacOS 14.1.1. The problem is present since at least MacOS 13.
When installed via NIX, the setting works correctly, so I think it might just be a problem with the DMG version.